The city's most vocal defender of rent control mounted attacks against the most vocal opponent of rent control when he was indicted for bank fraud.

Now the pro-rent control activist group, Cambridge Tenants' Union, is putting City Councillor William H. Walsh under fire once again by charging him with violating conflict of interest legislation.

Following Walsh's actions since 1989, CTU Co-Chair Michael H. Turk said the activist group has "a series of facts to buttress the allegations," but that he does not consider the council's nearly unanimous decision Monday night to launch an investigation a victory.

"What we're concerned about is the damage done to the institution of city government," Turk said. He added, however, that his group is "pleased that the council did decide to take the matter seriously."

Turk first presented his findings to the council on October 22 and requested a legal investigation. In addition to alleged wrongdoing by Walsh, CTU also levelled charges of ethics violation against Councillor Sheila T. Russell and Sally Ackerman, a member of the Rent Control Board and an investor in one of Walsh's condominium projects.

Walsh, however, countered the charges by maintaining his innocence. The fourth-term councillor--who has also said he is innocent of 59 federal counts of bank fraud--calls the council investigation of his dealings "a conspiracy."

"I never represented anyone at the Rent Control Board," said Walsh in a telephone interview yesterday. He said the interest groups in the city "run the government" and that the influence they wield is a "real tyranny."

Walsh, still under FBI investigation for fraudulent activities in his real estate ventures, added that the new charges are "politically motivated."

"It's whitewashes," said Walsh, raising his voice. "When it comes to me, everything's an open book, but when it comes to them, everything's a whitewash," said Walsh.

Walsh levelled charges of his own against other councillors, including Alice K. Wolf, who he said were also involved in potential conflicts of interest.

Walsh said that one Rent Control Board Attorney, Patricia Cantor, "harassed" him with the council investigation incident and even submitted a letter to The Boston Globe about him.

Walsh then filed a complaint to City Manager Robert W. Healy, saying the charge was "harassment."

Walsh said he filed the complaint because he believed an investigation would be a "waste of taxpayers' money."

The allegations against Walsh, a practicing lawyer, include using political clout to block a Rent Control Board inquiry into a colleague's actions and representing clients in matters concerning city agencies.

According to Turk, Walsh prevented the Rent Control Board from investigating Mary Praught, a lawyer in Walsh's law firm for an alleged scheme to rent out a rent-controlled apartment at market rates.